The present invention relates to a portable electronic medium which functions as a memory card, and in which a memory for storing data and a control circuit for controlling the memory are independently installed on the same card.
Where a memory for storing data and a control circuit (a control LSI) for controlling the memory are independently installed on the same card (a base board), it is general that they are soldered to the base board.
Owing to this structure, the memory can be easily replaced with a new one, and the control LSI can be detached for analysis.
In other words, a counterfeit can be made by merely replacing only the memory with another, or by increasing the storage capacity.
The present invention has been made in consideration of the above circumstances, and is intended to prevent the installation of a memory that does not correspond to the control circuit in use, thereby preventing fabrication of a counterfeit employing such a memory.
The present invention is also intended to prevent easy analysis of the control circuit in use.
According to the present invention, there is provided a portable electronic medium comprising: a base board on which wiring is provided; a first memory, installed on the base board, for storing data and a first certification key; and a control circuit including: a second memory for storing data and a second certification key; and a control section for controlling an operation of storing data in the first memory and an operation of reading the data from the first memory, the second memory and the control section being fabricated as a chip which is installed on the base board and connected to the base board, the control section checking whether the first certification key stored in the first memory coincides with the second certification key stored in the second memory, thereby determining whether or not the first memory is an intended one.
According to the present invention, there is also provided a portable electronic medium comprising: a base board on which wiring is provided; a first memory, installed on the base board, for storing data; and a control circuit including: a second memory for storing data and a first-memory-state information; and a control section for controlling an operation of storing data in the first memory and an operation of reading the data from the first memory, the second memory and the control section being fabricated as a chip which is installed on the base board and connected to the base board, the control section checking whether the first memory is in a state coinciding with first-memory-state information stored in the second memory, thereby determining whether or not the first memory is an intended one.
According to the present invention, there is further provided a portable electronic medium comprising: a base board on which wiring is provided; a first memory, installed on the base board, for storing data and encoded data obtained by encoding a first certification key; and a control circuit including: a second memory for storing data, a second certification key, an encoding key, and a decoding program; and a control section for controlling an operation of storing data in the first memory and an operation of reproducing the data from the first memory, the second memory and the control section being fabricated as a chip which is installed on the base board and connected to the base board, the control section decoding the encoded data stored in the first memory by use of the encoding key and decoding program stored in the second memory, and further checking whether a resultant certification key coincides with the certification key stored in the second memory, thereby determining whether or not the first memory is an intended one.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.